The Neutral Particle Beam system is a key component in the Strategic Defense Initiative defense scenario. It can discriminate between reentry vehicles containing warheads and high-replica decoys and other penetration aids in the midcourse flight regime. This ability to discriminate and kill these assets derives from the interactions between the neutral particle beam and the target materials, and from the detailed nature and quantity of the induced emissions generated by the interactions.
One such emission attractive for potential use is the neutron. A major problem in realizing the necessary discrimination capability involves neutron detection in a high background radiation environment, particularly in the case of a nuclear burst. No such detector has heretofore been available.
The advanced neutron detector of the present invention is capable of operating in the hostile exoatmospheric environment which includes albedo neutrons, gamma rays, and cosmic rays. The operating environment is made even more hostile by the presence of inadvertent and/or advertent nuclear bursts. Of particular concern are the late-time neutron and gamma rays due to nuclear bursts.
Consequently, a detector is needed which will enable execution of midcourse discrimination by the leading candidate observable, the neutral particle beam induced neutron yield as a measure of the mass of the body being probed. For such a detector to be useful, it must be high in efficiency, low in weight, and modest in cost. These objectives require a breakthrough in the neutron detector technology.
In a hostile space environment, especially during nuclear engagement, the background can be filled with high energy particles. The nuclear burst produced background neutron environment the detector sees could be a very large factor, typically 10 larger than the neutron signal produced by neutral particle beam interaction with the body being probed at ranges of interest. Therefore, a good detector must be able to discriminate targets within this hostile scenario. Furthermore, the required neutron detector must be highly efficient so that the detector weight and costs are affordable.